Rails 3 RoutingError: No route matches {:controller=>"user_sessions"} - ruby-on-rails

Question

I'll just try to outline this as high level as I can. I am trying to access http://localhost:3000/login
The error is:
No route matches {:controller=>"user_sessions"}
And it's erroring on this line in the new.html.erb file below:
<%= form_for(#user_session) do |f| %>
The route in routes.rb is:
match 'login' => 'user_sessions#new', :as => :login
The user_sessions_controller.rb is:
class UserSessionsController < ApplicationController
def new
#user_session = UserSession.new
end
def create
#user_session = UserSession.new(params[:user_session])
if #user_session.save
flash[:notice] = "Successfully logged in."
redirect_to root_path
else
render :action => 'new'
end
end
def destroy
#user_session = UserSession.find
#user_session.destroy
flash[:notice] = "Successfully logged out."
redirect_to root_path
end
end
And the actual view for the login page is as follows (new.html.erb):
<h1>Login</h1>
<%= form_for(#user_session) do |f| %>
<% if #user_session.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#user_session.errors.count, "error") %> prohibited this user from being saved:</h2>
<ul>
<% #user_session.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<p>
<%= f.label :login %><br />
<%= f.text_field :login %>
</p>
<p>
<%= f.label :password %><br />
<%= f.password_field :password %>
</p>
<p><%= f.submit "Submit" %></p>
<% end %>
Thank you.

Answer 1

Using form_for(#user_session) alone will try to build out the path using a resource you have defined in your routes.rb. Which you currently don't have (I'm assuming, as you didn't mention it. Please correct if I'm wrong.).
A few ways to go..
Add a resource and limit to the ones you need
resources :user_sessions, :only => [:create, :destroy]
These will use the default routing namings, but you can custom that up as you need.
Match out the routes you need.
match 'login' => 'user_sessions#create', :as => :post_login, :via => :post
View
= form_for(#user_session), :url => post_login_path do |f|
...